The 17th-ranked Irish already were expected to be young on defense in the season opener against Rice on Saturday. That's before learning they'd be without four players, three of them on defense, all under investigation by the university to determine whether they received improper assistance from others on papers and homework.

Kelly confirmed Tuesday that cornerback KeiVarae Russell, leading returning receiver DaVaris Daniels, defensive end Ishaq Williams and backup linebacker Kendall Moore will not play Saturday, saying he hasn't received any update into the investigation announced publicly by the university on Aug. 15.

When it comes to an academic process involving the honor code, it's out of his hands, Kelly said. That was the case when quarterback Everett Golson was suspended from the university last fall for academic impropriety.

"It does me no good to put a timetable on it. It does me no good to think about what day. I've moved on and the process will take care of itself," he said.

The four remained on the roster handed out Tuesday but were not included on a depth chart that had six freshmen and six sophomores on the two-deep on defense.

Andrew Trumbetti could become the first true freshman to start a season opener on the defensive line for Notre Dame since Anthony Weaver in 1998, although Trumbetti officially was listed as the backup Tuesday.

"There's a guy that's going to be on the edge of our defense that's going to play a lot of football for us. We're going to have to count on him to play very well for us," Kelly said.

"So there are five freshmen right there that are going to have to play some form of winning football for us immediately for us to have the kind of success that we want defensively," Kelly said.

Notre Dame will at least have a familiar face under center. Golson regained the starting quarterback job he lost due to academics in 2013, a year after leading the Irish to the BCS title game.

Though Kelly said throughout the spring and summer that sophomore Malik Zaire had a chance to be the starter, Golson won the position because of his overall understanding of the offense, how he's handled himself with the team and his leadership.

"He's put himself in that position to get that opportunity to be our starter against Rice," Kelly said. "There was competition and there will be competition. Everett's the starter for Rice and we hope he's the starter for the entire year. But we're all in this merit-based situation. We've got to win."

With a young, inexperienced defense, Kelly has said the Irish need to put up more points. He's hoping Golson's running ability will help them after they were one-dimensional with Tommy Rees at quarterback. Kelly said the Irish won't have to switch plays as often along the line of scrimmage with Golson at quarterback.

"Tommy needed to check a lot of plays. We won't have to block that end for Everett on every play. We had to for Tommy. He wasn't going to make the end miss," Kelly said.

The Irish have ranked in the top 50 in total defense four straight years under Kelly, but are switching to a more aggressive style under new defensive coordinator Brian VanGorder after Bob Diaco left to become head coach at Connecticut.

VanGorder paused last week when asked what it would take for Notre Dame to have a successful defense. He answered that he thinks the Irish have a "developmental defense."

"Maybe the best answer to that is, let's keep getting better as we go through the year. We have a lot of work to do. The players know it. But let's keep improving. Let's keep working. I don't know where we are right now. The one thing I do know is there's a lot better football in front of us," he said.

Kelly said although the Irish are young, he believes they have gifted athletes. Asked Tuesday what could be done to help the defense, Kelly quickly responded: "Score a lot of points. That will ease everybody's concern."

Rice won Conference USA last season with a 7-1 league record, but finished the season 10-4 after being routed by Mississippi State 44-7 in the Liberty Bowl.

Gone are quarterback Taylor McHargue and top running back Charles Ross, leaving junior Driphus Jackson to take over under center. Jackson came in for a concussed McHargue in the 2012 Armed Forces Bowl and went 15 for 21 for 264 yards and two TDs in a 33-14 win, but played sparingly last season.

Rice has dropped 21 consecutive games against ranked opponents, allowing an average of 54.3 points in its 11 losses since 2005.